Multiple diffusing nozzle



Aug. 21, 1928.

I L. DUFOUR MULTIPLE DIFFUSING NbZZLE Filed Jan. 6f 1925 Patented Aug. 21, 1928.

UNlTEDf -STA TE$ P TE T. OFFICE LEON. nvroun, F VEBSOIX, swrrznR Ann.

ULTIPLE mrrusmo NOZZLE.

Application. filed Hanan 6, 192% Serial No. 8 96,'and in Germany January 19, 19 24.

The efiiciency of difiusing nozzles or diilus ers whichjare intended to. convert the velocity of a fluid into pressure and which generally consist of a nozzle continuously widening towards its outlet is only a goodfone, it the angle formed by two diametrically opposed generatrix sides is not far from about This angle varies according to the kind of fluid, the velocityand theiorm of the crosssection of the'nozzle. thetaperistoo steep the fluid gets detachedfrorn the walls of the nozzle and the efficiency will be less.

There are cases wherethe diii'erence oi? the velocity at'the inlet and outlet of. the nozzle which difierence is to be converted into pressure is very considerable. Then it is necessary if the angle of 10is to be observed to employ nozzles of; considerable length... -This however will be impossible sometimes.

It is the object of the present invention to provide relatively short nozzles even if the sectional area. of the outlet differs greatly from that of the inlet and yet to retain the same efficiency as with the best known dilfuser nozzles. The difiusernozzle according to the present invention is combined of several diffusing elements where th-e wallsare arranged so as to produce a good efiiciency. The ele' ments are adjoined in such a way that the angle between the diametrically opposed generatrices of the outer walls of the whole d1ffuser is considerably larger than the-usual angle of the best efficiency. It will be easily understood that such a combined diffuser is considerably shorter than one having a single passageway and having the sametaper as one single element of a combined diffuser according to the present invention. Of course a comparison can only be :made between diffusers having inlets and outlets of equal size. 7 V

In the drawings I have shown a number of forms preferred by me. 5 Figs. 1 and 2 are a longitudinal sectionand an end elevation of a first form.

Figs. 3 and 4 longitudinal section and end elevation of a second form;

Figs. 5 and 6 longitudinal section and .end elevation of a third form,

Figs. .7 and 8 longitudinal section and end elevation of a fourthform.;

Figs. 9 and10 longitudinal section and end 7 elevation of a fifth form, and

Figs. 11and 12 longitudinal section and a cross section of a sixth form.

In the annexed drawing Figs. 1 and 2 represent a difluser nozzle of a known form hava one single passage way of a. quadratic cross-section. and walls opening at an angle oflO".

The fluid enters at. lat a certain speed and at a certain pressure in the direction of t-he arrow 2 andis discharged at 3 with a dimin:

ished speed but with a greater pressure and in the direction of the arrow l. 7

Figs. 3 and 4 rep resentfia diitusen nozzle 1 according to the present iinventioncombined I the nozzle represented in Figs. 1 and 2 and the whole sectional 'areaotthe outlet at 6 is likewise the same as that of the foregoing apparatus. The opening angle'of each elementis 10? and the efiici-ency about the same. The

total length however is only half of the n ozzle shown in Figs. 1 and 2.

The Figs. 5 and 6 represent a difiuser noz-v zle having sixteen .coinbined elements, each element of quadratic cross-section. T The whole inlet areaat 7 and the whole outlet area at 8 are equal to the respective cross sections of the nozzles represented in Figs. 1 and 2. The opening angle of each element is 10 and therefore the efiici-ency nearly the same as in the first nozzle, the length however is one fourth as much. 1 a In the nozzles shown in Figures?) to G the cross 'sectionof each element is-quadratic,- but this is not'necessarilyso. i J

As shown in Figs. 7 and 8 the elements could also be arranged around a central one.

In these figures a conical element 9 tapered at an angle of 10 is surrounded by two other concentrical elements '10 and 11. Both have annular cross-sections of gradually increas= lng areas that is to say, the opposite walls in each single element thusformed include angles of about 10 or the angle of divergence in the three truncated cones shown in Figs.

7' and 8 will'alnount to 10.for the central f cone, 3 0 for the next annular cone and 50 for the outer annular cone. The outer wall of the third element is also the shell of the whole nozzle. The elements are strutted at V 12 so as to form one rigid body.

In the Figs. 9 and 10 another form of the nozzle is shown. The outer shell 13is likewise a conical tube, but the single elements are obtained by winding a thin body for instance a sheet iron into a conical splral Where the generatrices of opposite sides are including an angle of The said shell could also be a conical tube into which said spiral is inserted.

In the Figs. 11 and 12 a last example of a combined diffuser nozzle is shown which could be used as a suction pipe of a hydraulic turbine wheel. The central axis of the spiral is a column 15 standing on the floor 16 of the tail-race and extended to the top of spiral at 17 The spiral itself is constituted of two walls 18, 19 beginning at the center where they are joined and ending after several turns into a surrounding circle which is enclosed by an outer shell 20 generally made of concrete. Here also as may he concluded from Fig. 11 the spirals are conical spirals where the generatrices of opposite sides are diverging at an angle of 10.

This invention allows not only to build diffuser of a smaller size having a good efiicicncy but also to use diffusers with smaller angles than 10 which will convert velocity of a fluid into pressure with a better eliiciency and avoiding the use of relatively long conduits.

Such combined diflusers may be employed in many cases, as for instance for the exhaust of internal combustion engines in order to convert the velocity of the exhaust gases into a vacuum at the inlet of the diffuser and to relieve the cylinder from the residues of combustion and to provide the same with fresh mixture or With scavenging air.

Such combined difluser nozzles may also be substituted for the suction conduits of a reaction turbine. In this case the velocity of the water at a smaller suction head is much better utilized which sometimes is of great importance.

Having now particularly described my invention, what 1 claim is:

A multiple diffusing nozzle for converting the velocity of a fluid into pressure and constituted of a compound element having a plurality of passages each defined by uniformly diverging walls, the opposin walls of each passage enclosing angles of sifiistantially 10, the whole to the effect that the multiple passage nozzle possesses a total outlet aperture considerably larger than that which could be obtained with a single passage nozzle having the same length and the same size of inlet orifice.

In testimony whereof I aflix my signature.

LEON DU FOUR. 

